Members of this protein family are exosortase-related proteins found always in association with a member of family TIGR04127, a small, hydrophobic, uncharacterized protein limited to the Bacteriodetes. Exosortases are proposed transpeptidases with a cysteine active site (3.4.22.-), but usually are associated with specific C-terminal target motifs (PEP-CTERM, PEF-CTERM, PGF-CTERM, etc).